Patent document 1 (U.S. Pat. No. 3,728,495) discloses “Multilayer film mask defect inspection method and apparatus” as an example of a technique for detecting the position of a defect existing on a semiconductor exposure mask by scattered light.
Patent document 2 (Jpn. Pat. Appln. KOKAI Publication No. 2006-80437) discloses “Mask blanks inspection method and mask blanks inspection tool” as an example of a technique for normalization with use of an intensity in a peripheral region at a time of inspecting a defect existing on a semiconductor exposure mask.